Rheostat



Patented July 2, 1929.

UNITED STATES PATENT oFFlci-:.-

FOSTER F. HILLIX, OF CLEVELAND, OHIO, ASSIGNOR, BY MESNEl ASSIGNMENTS,TO WHITE SEWING MACHINE CORPORATION, OF CLEVELAND, OHIO, A CORPORATIONOF DELAWARE.

nHEosTAT.

- .Application led November 25, 1922. Serial No. 603,265.

This invention relates to improvements in rheostats particularly thoseadapted for controlling small motors such as are employed for operatingsewing machines and other motor driven apparatus.

More particularly the invention aims to provide an improved rheostathavingcertain advantages to be referred to presently adapted to rest onthe lloor so as to be controlled by the foot of the operator, thoughmany features of the invention may be utilized in rheostats adapted tobe otherwise located and controlled or operated.

Among the objects of the present invention are to obtain a rheostatwhich is highly elhcient and durable and in which are embodied thefeatures of compactness, light weight, simplicity of construction andease and cheapness of assembly and disassembly making it possible tomanufacture the rheostat at low cost. A further and closely alliedobjectv is to provide a construction adapted particularly for quantityproduction. l

Still further the invention aims to provide what may be termed amultiple unit rheostat in the sense that it is composed of unitsconsisting particularly of the casing with the motion imparting memberapplied to it, and the resistor unit consisting of a self-containedunitary element adapted to be applied as a unit to the casing or removedtherefrom, and including the insulating base, the resistance materialand the contact mechanism.

The invention may be briel-y summarized as consisting in certain noveldetails of con struction, and combinations and arrangements of partswhich will be described in the specification and pointed out in theappended claim. v V

In the accompanying sheets of drawings wherein I have illustrated thepreferred embodiment of the invention, Fig. 1 is a vertical sectionalview of my improved rheostat; Fig. 2 is a horizontal sectional viewsubstantially along the line 2 2 of Fig. 1 looking in the directionindicated by the arrows; Fig. 3 is a bottom view of the lower half ofthe casing removed and lookingup at the bottom of the resistor unit;Fig. 4 is a detail sectional view substantially along the line 4-4 ofFig. 6 showing how the vertical rocking movement of the foot controlledlever on top of the casing is transmitted to the horizontal swingingmember on'the inner side of the casin which shifts the arm of theresistor unit; ig. 5 is In this instance my improved rheostat is adaptedto rest on the floor and to be foot operated as mentioned above,l thoughas before stated, that is not an essential characteristic or feature ofmy improved rheostat. This rheostat is composed of a casing formed inthis instance of two telescopic parts, preferably stamped from sheetmetal, and including an upper main body portion 10 and a lower or bottomportion 11 which telescopically engage each other as clearly shown inthedrawings, -and may, if desired, be held together simply by thefrictional engagement of the parts. In this case the lower part of thebody member 10 is somewhat distended, and the base or bottom member 11fits intoit. The lower member 11v is provided withy rubber feet 13 sothat the rheostat will. not readily slide over the Hoor or mar a highlypolished floor. The upper or body member 10 is preferably provided withperforations and slots 10 punched in it. principally to provide forcirculation of air. i

The casing described abovel with the motion imparting mechanism to bereferred to presently may be regarded as one unit of the rheostat.

The resistance and contact portions constitute a second unit adapted tobe applied to or removed as a whole from theA casing unit. This secondunit, which will be termed the resistor unit, consists in this case of aliat body or base 12 of porcelain or other suitable insulatin material,suitably grooved or slotted to receive the resistance wire 13. At

one end of the base- 12 these wires are conf nected to a series ofcontacts or buttons 14.

The resistor unit also includes a metal rheostat arm 15 whose free end15 is adapted to sweep over the contacts 14 to gradually cut theresistance section out of .or into the circuit in the usual mannerdepending upon whether the arm is swung from or toward olf position. Thearm 15 is pivoted at 16 to the end of theins'ulating base 12 opposite tothat having the contacts 14, andthis arm is electrically connected to acontact strip 17, in turn electrically connected to a bindlng post screw18 to which'one of a pairof conductors 19 is adapted to be connected.One end of the which are secured to and extend down from' the inside ofthe top wall of the casing member 10. These straps may be secured to thecasing member 10 by being spot welded or otherwise. These supportingstraps or brackets 23 are spaced apart lengthwise ot' the casing adistance substantially equal to the insulating base 12 and when theresistor unit is set into-the casing member 10 it engages .inwardlyextending ears 23 which project inwardly from the straps 23. IVhen theresistor unit is set in, additional ears 23 are bent inwardl over thebottom of the base 12 so as to ho d it in place. To relnove the resistorunit it is simply necessary to straighten out the bottom ears 23b andlift the resistor unit out of the casing. i

Motion is transmitted to the rheostat arm 15 by an outside controllingmember here shown as a foot pcd-al or lever 24. This member which ispreferably pressed out otl sheet metal is pivotally connected by atransverse pin 25 to a pair of up'standing ears of a pair of brackets 26secured to the top of the casing as clearly shown in Fig. 6. Thesebrackets may be secured in various ways to the casing, but in thisinstance they are provided with tongues 26l which are extended throughslots in the casing and are bent laterally to hold them in place.

The part of the edal or lever 24 which is pivoted to the brac ets 26 isprovided with a pair of downwardly extending ears through which thepivot pin 25 passes. One of these ears is provided with an extension 24which projects through a slot in the top of the casing member 10 andimparts motion to a horlzontally disposed and horizontally swlngmgshifting member 27 p'ivotally connected by a short pin 28 to the underside of the upper casing member 10'. This shifting member 27 carries afibre or other suitable msulatmg block 29 which has a centrally disposedslot 29 into which projects the pin 22 extendmg up from the rheostat arm15. In this instance the bottom of the extension 24a at the pivoted endof the lever or pedal 24 is provided with a short gear segment 24b whichmeshes with a companion gear segment 27@L projecting laterally from thehorizontally disposed shifting member 27. Thus when the foot lever isrocked vertically horizontal swinging motion is imparted to the shiftingmember 27 and the latter in turn imparts horizontal swinging motion tothe rheostat arm 15.

' The other ear at the pivoted end of the lever or pedal 24 is providedwith an extension 24" which projects down through a slot in the top ofthe upper casing member 1() toward the bottom otl the rheostat, and thelower end of this extension has connected to it a. spring 30 whichextends along the bottom of the casing' and has its opposite endanchored at 31a. '.lhis spring which is normall \y under tension, keepsthe t'ree end of the pedal 24 elevated, and therefore normally holds therheostat arm in its off position. YVhen the. pedal is depressed therheostat arm is swung as already explained until finally the free endot' the rheostat arm engages the final contact or button 14.l Thedownward movement of the pedal is stopped by an abutment 31 on the endof the casing, which abutment is in this instance engaged by anextension 24". When the pedal is released, the spring 30 restores theparts to normal position including off position for the rheostat arm 15.It might be stated at this point that the movements of the rheostat armare limited by a pair of upstanding ears 32 and 33 shown in Fig. 2, oneof these ears being on a clip to which the ott button or contact isconnected, and the other ear being formed as a part of the conductingstrip 20 extending lengthwise of and along the top of the base 12 asalready explained. l

It will be scen from the above that the casing, and particularly theupper casing member 10 and the motion transmitting mechanism forV therheostat arm may be formed as one part or unit and the resistance partmay be formed as a second unit, and that the latter can be slipped intoplace and thus operatively connected to the motion transmittingmechanism and can be readily removed from the casing as a unit withoutdisturbing the motion transmit-ting mechanism.

Likewise it will be seen that vthe parts can be formed very largely ofstampings and that' the construction is such that the assembly of theparts can be very readily made. Furthermore, notwithstanding the actthatthe parts can be formed and assembled inexpensively, a rheostat which iseiiicient and possesses to a high degree the feature of durability isprovided.

The manner in which the resistor unit can be applied and removed fromthe casing is an important feature of my improved construction forshould the .resistance wire be burned out or should the rheostatotherwise needrepairs, the resistor unit can be removed by aninexperienced person and repaired and replaced, or replaced with a newresistor unit if the latter be necessitated.

In conclusion it might be stated that to render this device effective,and particularly to prevent the rheostat being pushed along the floorwhen the operator intends to depress lthe lever, it is desirable thatthe top of the lever be smooth, and that the free end of the lever begiven a downward curvature substantially as shown in the drawings sothat when the operator places his foot on the lever and rocks his footon the rear point of the heel the foot will slide over the lever and atthe same time depress it. It might be mentioned that in the drawings thelever is shown partly depressed or in substantially its mid Iposition toeconomize space, but it will be apparent that when the lever is in itshighest position the curvature which is given to the lever and itssmooth surface will materially assist the depression of the level' asthe foot Which engages it is rocked.

While I have shown the preferred construction, I do not desire to beconfined to the exact details shown, but aim in my claim to cover allmodifications Which do not involve a departure from thenspirit and scopeof my invention in its broadest aspect.

Having described my invention, l claim:

A rheostat comprising a casing, a resistor unit Within said casing andincluding a inovable contact arm, and a member .mounted on the exteriorof said casing and operatively connected with said movable arm andadapted to move in a plane .at substantially right angles to said arm.

ln testimony whereof, I hereunto affix my signature.

FOSTER F. HILLIX.

